Gut microbiota in colorectal cancer: mechanisms of action and clinical applications

Factors of faecal microbiota transplantation applied to cancer management

The homeostasis of the microbiota is essential for human health. In particular, the gut microbiota plays a critical role in the regulation of the immune system. Thus, faecal microbiota transplantation (FMT), a technology that has rapidly developed in the last decade, has specifically been utilised for the treatment of intestinal inflammation and has recently been found to be able to treat tumours in combination with immunotherapy. FMT has become a breakthrough in enhancing the response rate to immunotherapy in cancer patients by altering the composition of the patient's gut microbiota. This review discusses the mechanisms of faecal microorganism effects on tumour development, drug treatment efficacy, and adverse effects and describes the recent clinical research trials on FMT. Moreover, the factors influencing the efficacy and safety of FMT are described. We summarise the possibilities of faecal transplantation in the treatment of tumours and its complications and propose directions to explore the development of FMT.

Metabolic interactions of host-gut microbiota: New possibilities for the precise diagnosis and therapeutic discovery of gastrointestinal cancer in the future-A review

Gastrointestinal (GI) cancer continues to pose a significant global health challenge. Recent advances in our understanding of the complex relationship between the host and gut microbiota have shed light on the critical role of metabolic interactions in the pathogenesis and progression of GI cancer. In this study, we examined how microbiota interact with the host to influence signalling pathways that impact the formation of GI tumours. Additionally, we investigated the potential therapeutic approach of manipulating GI microbiota for use in clinical settings. Revealing the complex molecular exchanges between the host and gut microbiota facilitates a deeper understanding of the underlying mechanisms that drive cancer development. Metabolic interactions hold promise for the identification of microbial signatures or metabolic pathways associated with specific stages of cancer. Hence, this study provides potential strategies for the diagnosis, treatment and management of GI cancers to improve patient outcomes.

Metabolic dysfunction-associated steatotic liver disease and extrahepatic gastrointestinal cancers

Metabolic dysfunction-associated steatotic liver disease (MASLD) poses a significant and ever-increasing health and economic burden worldwide. Substantial epidemiological evidence shows that MASLD is a multisystem disease that is associated not only with liver-related complications but is also associated with an increased risk of developing cardiometabolic comorbidities and extrahepatic cancers (principally gastrointestinal [GI] cancers). GI cancers account for a quarter of the global cancer incidence and a third of cancer-related deaths. In this narrative review, we provide an overview of the literature on (a) the epidemiological data on the risk of non-liver GI cancers in MASLD, (b) the putative mechanisms by which MASLD (and factors linked with MASLD) may increase this risk, and (c) the possible pharmacotherapies beneficially affecting both MASLD and extrahepatic GI cancer risk. There are multiple potential pathophysiological mechanisms by which MASLD may increase extrahepatic GI cancer risk. Although further studies are needed, the current evidence supports a possible extrahepatic carcinogenic role for MASLD, regardless of obesity and diabetes status, thus highlighting the potential role of tailoring cancer screening for individuals with MASLD. Although there are conflicting data in the literature, aspirin, statins and metformin appear to exert some chemo-preventive effects against GI cancer.

Traditional medicine Xianglian pill suppresses high-fat diet-related colorectal cancer via inactivating TLR4/MyD88 by remodeling gut microbiota composition and bile acid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Previous studies have revealed that a high-fat diet (HFD) promotes the progression of colorectal cancer (CRC) in close association with disturbances in the intestinal flora and metabolic disorders. Xianglian pill (XLP) is a well-established traditional prescription with unique advantages in controlling intestinal flora imbalance and inflammation. However, its therapeutic effects on HFD-related CRC remain largely unknown.

AIM OF THE STUDY

The primary objective of this research was to investigate the anticancer mechanism of XLP in countering HFD-related CRC.

MATERIALS AND METHODS

The protective effect of XLP was evaluated using azoxymethane (AOM) and dextran sulfate sodium (DSS)-induced CRC model of mice exposed to a HFD. The degree of colorectal carcinogenesis, including body weight, colon length, and histopathology, was measured in mice treated with XLP and untreated mice. The effect of XLP on gut microbiota and its metabolites was detected using 16S rDNA and liquid chromatography/mass spectrometry analysis. Furthermore, a "pseudo-sterile" mouse model was constructed using antibiotics (Abx) to verify whether the gut microbiota and metabolites play a role in the pathogenesis of CRC.

RESULTS

XLP inhibited colorectal tumorigenesis in a dose-dependent fashion. Our findings also highlighted that XLP protected the integrity of the intestinal barrier by reducing the expression of pro-inflammatory cytokines, such as IL-6 and TNF-α, as well as the infiltration of pro-inflammatory macrophages. Mechanistically, XLP inhibited the TLR4/MyD88 pathway. Notably, the XLP treatment increased the proportion of probiotics (particularly Akkermansia) and significantly reduced fecal deoxycholic acid (DCA), a microbiota-derived metabolite of bile acids (BA) closely related to Muribaculaceae. Furthermore, after Abx treatment, XLP showed no clear antitumor effects on CRC. Simultaneously, DCA-supplemented feedings promoted colorectal tumorigenesis and provoked obvious colonic inflammation, M1 macrophage infiltration, and colonic injury. In vitro, the results of RAW-264.7 macrophages and normal intestinal epithelial cells treated with DCA corroborated our in vivo findings, demonstrating consistent patterns in inflammatory responses and intestinal barrier protein expression.

CONCLUSION

Our findings suggest that XLP inhibits colorectal cancer associated with HFD via inactivating TLR4/MyD88 by remodeling gut microbiota composition and BA metabolism.

Aged microbiota exacerbates cardiac failure by PPARα/PGC1α pathway

The dysbiosis of gut microbiota with aging has been extensively studied, revealing its substantial contribution to variety of diseases. However, the impact of aged microbiota in heart failure (HF) remains unclear. In this study, we employed the method of fecal microbiota transplantation (FMT) from aged donors to investigate its role in the context of HF. Our results demonstrate that FMT from aged donors alters the recipient's gut microbiota composition and abundance. Furthermore, FMT impairs cardiac function and physical activity in HF mice. Aged FMT induces metabolic alterations, leading to body weight gain, impaired glucose tolerance, increased respiratory exchange ratio, and enhanced fat accumulation. The epicardium of aged FMT recipients shows fat accumulation, accompanied by cardiomyocyte hypertrophy, cardiac fibrosis and increased cellular apoptosis. Mechanistically, aged FMT suppresses the PPARα/PGC1α signaling pathway in HF. Notably, activation of PPARα effectively rescues the metabolic changes and myocardial injury caused by aged FMT. In conclusion, our study emphasizes the role of the PPARα/PGC1α signaling pathway in aged FMT-mediated HF.

Review of METTL3 in colorectal cancer: From mechanisms to the therapeutic potential

N6-methyladenosine (m6A), the most abundant modification in mRNAs, affects the fate of the modified RNAs at the post-transcriptional level and participants in various biological and pathological processes. Increasing evidence shows that m6A modification plays a role in the progression of many malignancies, including colorectal cancer (CRC). As the only catalytic subunit in methyltransferase complex, methyltransferase-like 3 (METTL3) is essential to the performance of m6A modification. It has been found that METTL3 is associated with the prognosis of CRC and significantly influences various aspects of CRC, such as cell proliferation, invasion, migration, metastasis, metabolism, tumor microcirculation, tumor microenvironment, and drug resistance. The relationship between METTL3 and gut-microbiota is also involved into the progression of CRC. Furthermore, METTL3 might be a viable target for CRC treatment to prolong survival. In this review, we comprehensively summarize the function of METTL3 in CRC and the underlying molecular mechanisms. We aim to deepen understanding and offer new ideas for diagnostic biomarkers and therapeutic targets for colorectal cancer.

Curcumin suppresses colorectal tumorigenesis through restoring the gut microbiota and metabolites

BACKGROUND

Curcumin has been reported to have activity for prevention and therapy of CRC, yet its underlying mechanisms remain largely unknown. Recently, emerging evidence suggests that the gut microbiota and its metabolites contribute to the causation and progression of Colorectal cancer (CRC). In this study, we aimed to investigate if curcumin affects the tumorigenesis of CRC by modulating gut microbiota and its metabolites.

METHODS

Forty male C57BL/6JGpt mice were randomly divided into four groups: negative control (NC), curcumin control, CRC model, and curcumin treatment (CRC-Cur) groups. CRC mouse model was induced by using azoxymethane (AOM) and dextran sodium sulfate (DSS), and the mice in CRC model and curcumin treatment groups received oral PBS or curcumin (150 mg/kg/day), respectively. Additionally, fecal samples were collected. 16 S rRNA sequencing and Liquid Chromatography Mass Spectrometry (LC-MS)-based untargeted metabolomics were used to observe the changes of intestinal flora and intestinal metabolites.

RESULTS

Curcumin treatment restored colon length and structural morphology, and significantly inhibited tumor formation in AOM/DSS-induced CRC model mice. The 16S rRNA sequencing analysis indicated that the diversity and richness of core and total species of intestinal microflora in the CRC group were significantly lower than those in the NC group, which were substantially restored in the curcumin treatment group. Curcumin reduced harmful bacteria, including Ileibacterium, Monoglobus and Desulfovibrio, which were elevated in CRC model mice. Moreover, curcumin increased the abundance of Clostridia_UCG-014, Bifidobacterium and Lactobacillus, which were decreased in CRC model mice. In addition, 13 different metabolites were identified. Compared to the NC group, ethosuximide, xanthosine, and 17-beta-estradiol 3-sulfate-17-(beta-D-glucuronide) were elevated in the CRC model group, whereas curcumin treatment significantly reduced their levels. Conversely, glutamylleucine, gamma-Glutamylleucine, liquiritin, ubenimex, 5'-deoxy-5'-fluorouridine, 7,8-Dihydropteroic acid, neobyakangelicol, libenzapril, xenognosin A, and 7,4'-dihydroxy-8-methylflavan were decreased in the CRC group but notably upregulated by curcumin. Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis revealed enrichment in seven pathways, including folate biosynthesis (P < 0.05).

CONCLUSIONS

The gut microecological balance was disrupted in AOM/DSS-induced CRC mice, accompanied by metabolite dysbiosis. Curcumin restored the equilibrium of the microbiota and regulated metabolites, highly indicating that curcumin may alleviate the development of AOM/DSS induced colorectal cancer in mice by regulating intestinal flora homeostasis and intestinal metabolites.

Metagenomic analysis of colonic tissue and stool microbiome in patients with colorectal cancer in a South Asian population

BACKGROUND

The gut microbiome is thought to play an important role in the development of colorectal cancer (CRC). However, as the gut microbiome varies widely based on diet, we sought to investigate the gut microbiome changes in patients with CRC in a South Asian population.

METHODS

The gut microbiome was assessed by 16s metagenomic sequencing targeting the V4 hypervariable region of the bacterial 16S rRNA in stool samples (n = 112) and colonic tissue (n = 36) in 112 individuals. The cohort comprised of individuals with CRC (n = 24), premalignant lesions (n = 10), healthy individuals (n = 50) and in those with diabetes (n = 28).

RESULTS

Overall, the relative abundances of genus Fusobacterium (p < 0.001), Acinetobacter (p < 0.001), Escherichia-Shigella (p < 0.05) were significantly higher in gut tissue, while Romboutsia (p < 0.01) and Prevotella (p < 0.05) were significantly higher in stool samples. Bacteroides and Fusobacterium were the most abundant genera found in stool samples in patients with CRC. Patients with pre-malignant lesions had significantly high abundances of Christensenellaceae, Enterobacteriaceae, Mollicutes and Ruminococcaceae (p < 0.001) compared to patients with CRC, and healthy individuals. Romboutsia was significantly more abundant (p < 0.01) in stool samples in healthy individuals compared to those with CRC and diabetes.

CONCLUSION

Despite marked differences in the Sri Lankan diet compared to the typical Western diet, Bacteroides and Fusobacterium species were the most abundant in those with CRC, with Prevotella species, being most abundant in many individuals. We believe these results pave the way for possible dietary interventions for prevention of CRC in the South Asian population.

A probiotic Limosilactobacillus fermentum GR-3 mitigates colitis-associated tumorigenesis in mice via modulating gut microbiome

Bacterial therapy for colorectal cancer (CRC) represents a burgeoning frontier. The probiotic Limosilactobacillus fermentum GR-3, derived from traditional food "Jiangshui", exhibited superior antioxidant capacity by producing indole derivatives ICA and IPA. In an AOM/DSS-induced CRC mouse model, GR-3 treatment alleviated weight loss, colon shortening, rectal bleeding and intestinal barrier disruption by reducing oxidative stress and inflammation. GR-3 colonization in distant colon induced apoptosis and reduced tumor incidence by 51.2%, outperforming the control strain and vitamin C. The beneficial effect of GR-3 on CRC was associated with gut microbiome modulation, increasing SCFA producer Lachnospiraceae NK4A136 group and suppressing pro-inflammatory strain Bacteroides. Metagenomic and metabolic analyses revealed that GR-3 intervention upregulated antioxidant genes (xseA, ALDH) and butyrate synthesis gene (bcd), while increasing beneficial metabolites (SCFAs, ICA, IPA, VB12 and VD3) and reducing harmful secondary bile acids. Overall, GR-3 emerges as a promising candidate in CRC therapy, offering effective gut microbiome remediation.

Associations between low- and high-fat dairy intake and recurrence risk in people with stage I-III colorectal cancer differ by sex and primary tumour location

We previously demonstrated that intake of low-fat dairy, but not high-fat dairy, was associated with a decreased colorectal cancer (CRC) recurrence risk. These risks, however, may differ by sex, primary tumour location, and disease stage. Combining data from two similar prospective cohort studies of people with stage I-III CRC enabled these subgroup analyses. Participants completed a food frequency questionnaire at diagnosis (n = 2283). We examined associations between low- and high-fat dairy intake and recurrence risk using multivariable Cox proportional hazard models, stratified by sex, and primary tumour location (colon and rectum), and disease stage (I/II and III). Upper quartiles were compared to lower quartiles of intake, and recurrence was defined as a locoregional recurrence and/or metastasis. During a median follow-up of 5.0 years, 331 recurrences were detected. A higher intake of low-fat dairy was associated with a reduced risk of recurrence (hazard ratio [HR]: 0.60, 95% confidence interval [CI]: 0.43-0.83), which seemed more pronounced in men (HR: 0.51, 95% CI: 0.34-0.77) than in women (HR: 0.84, 95% CI: 0.47-1.49). A higher intake of high-fat dairy was associated with an increased risk of recurrence in participants with colon cancer (HR: 1.60, 95% CI: 1.03-2.50), but not rectal cancer (HR: 0.88, 95% CI: 0.54-1.45). No differences in associations were observed between strata of disease stage. Concluding, our findings imply that dietary advice regarding low-fat dairy intake may be especially important for men with CRC, and that dietary advice regarding high-fat dairy intake may be specifically important in people with colon cancer.

Host-Gut Microbiota Metabolic Interactions and Their Role in Precision Diagnosis and Treatment of Gastrointestinal Cancers

The critical role of the gut microbiome in gastrointestinal cancers is becoming increasingly clear. Imbalances in the gut microbial community, referred to as dysbiosis, are linked to increased risks for various forms of gastrointestinal cancers. Pathogens like Fusobacterium and Helicobacter pylori relate to the onset of esophageal and gastric cancers, respectively, while microbes such as Porphyromonas gingivalis and Clostridium species have been associated with a higher risk of pancreatic cancer. In colorectal cancer, bacteria such as Fusobacterium nucleatum are known to stimulate the growth of tumor cells and trigger cancer-promoting pathways. On the other hand, beneficial microbes like Bifidobacteria offer a protective effect, potentially inhibiting the development of gastrointestinal cancers. The potential for therapeutic interventions that manipulate the gut microbiome is substantial, including strategies to engineer anti-tumor metabolites and employ microbiota-based treatments. Despite the progress in understanding the influence of the microbiome on gastrointestinal cancers, significant challenges remain in identifying and understanding the precise contributions of specific microbial species and their metabolic products. This knowledge is essential for leveraging the role of the gut microbiome in the development of precise diagnostics and targeted therapies for gastrointestinal cancers.

PRM1201 effectively inhibits colorectal cancer metastasis via shaping gut microbiota and short- chain fatty acids

BACKGROUND

PRM1201 is a traditional medicine with beneficial effects against colorectal cancer (CRC) metastasis. However, the underlying mechanism of this action remains to be determined.

HYPOTHESIS

Remodeling microbiota and short-chain fatty acids (SCFAs) metabolism might be a potential mechanism to explain the anti-metastatic action of PRM1201, as this gut-microbiota dependent effect involves downregulation of histone deacetylation and EMT.

METHODS

To investigate this possibility, clinical specimens were sequenced and the correlation between the anti-metastatic efficacy of PRM1201 and the restoration of SCFA-producing bacteria was studied. To obtain solid causal evidence, a mouse metastasis model was established to detect the influence of PRM1201 on cancer metastasis. Specifically, 16S amplicon sequencing, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, and bacterial manipulation were used to examine the gut microbiota-driven anti-metastatic action of PRM1201.

RESULTS

Clinical data showed that PRM1201 increased both the number of SCFA-producing bacteria and generation of SCFAs in the feces of CRC patients. A positive correlation between the anti-metastatic efficacy of PRM1201 and the restoration of SCFAs observed. The animal experiments demonstrated that PRM1201 effectively blocked CRC metastasis in a dose-dependent manner. PRM1201 treatment modulated the composition of gut microbiota, and promoted the proliferation of beneficial SCFAs producers such as Akkermansia, Lachnospiraceae_NK4A136_group and Blautia, while simultaneously reducing the abundance of pathogenic bacteria like Escherichia-Shigella. In addition, PRM1201 led to augmentation of SCFAs content. Further results indicated that the anti-cancer metastatic mechanism of PRM1201 was linked to inhibition of histone deacetylation and suppression of epithelial-to-mesenchymal transition (EMT) in metastatic lesions. Microbiota depletion treatment and fecal microbiota transplantation (FMT) underscored the microbiota-dependent nature of this phenomenon. Moreover, this anti-colorectal cancer metastatic effect and mechanism of total SCFAs and single SCFA were also confirmed.

CONCLUSION

In summary, PRM1201 exerts its anti-metastatic effects by modulating SCFA-producing bacteria and enhancing the production of SCFAs. Furthermore, the prebiotic-like actions of PRM1201, along with the PRM1201-treated bacteria, function as inhibitors of histone deacetylases (DHACs) thereby effectively suppressing EMT events.

Microbial mysteries: Staphylococcus aureus and the enigma of carcinogenesis

Staphylococcus aureus, a common human pathogen, has long been the focus of scientific investigation due to its association with various infections. However, recent research has unveiled a tantalizing enigma surrounding this bacterium and its potential involvement in carcinogenesis. Chronic S. aureus infections have been linked to an elevated risk of certain cancers, including skin cancer and oral cancer. This review explores the current state of knowledge regarding this connection, examining epidemiological evidence, pathogenic mechanisms, and biological interactions that suggest a correlation. Although initial studies point to a possible link, the precise mechanisms through which S. aureus may contribute to cancer development remain elusive. Emerging evidence suggests that the chronic inflammation induced by persistent S. aureus infections may create a tumor-promoting environment. This inflammation can lead to DNA damage, disrupt cellular signaling pathways, and generate an immunosuppressive microenvironment conducive to cancer progression. Additionally, S. aureus produces a variety of toxins and metabolites that can directly interact with host cells, potentially inducing oncogenic transformations. Despite these insights, significant gaps remain in our understanding of the exact biological processes involved. This review emphasizes the urgent need for more comprehensive research to clarify these microbiological mysteries. Understanding the role of S. aureus in cancer development could lead to novel strategies for cancer prevention and treatment, potentially transforming therapeutic approaches.

A review of healthy role of dietary fiber in modulating chronic diseases

Dietary fiber (DF) is considered an interventional diet beneficial for human health. High DF intake effectively reduces the incidence of three major chronic diseases, type 2 diabetes (T2DM), cardiovascular disease (CVD), and colorectal cancer (CRC). The health benefits of DF are closely related to their physicochemical properties with major positive roles in human digestion and intestinal health. However, mechanisms linking DF with diseases remain unclear. The development of genomics, metabolomics, and immunology, and the powerful combination of animal models and clinical trials, have facilitated a better understanding of the relationships between DF and diseases. Accumulating evidence suggests that the physical existence of DF and DF-microbiota interaction are the key parameters controlling the action mechanisms of DF in chronic diseases. Therefore, this review discusses the potential mechanism of DF modulating T2DM, CVD, and CRC, therefore providing a theoretical basis for more effective use of DF to intervene in chronic diseases.

Harmony unveiled: Intricate the interplay of dietary factor, gut microbiota, and colorectal cancer-A narrative review

Diet plays a critical role in shaping the gut microbiome, which in turn regulates molecular activities in the colonic mucosa. The state and composition of the gut microbiome are key factors in the development of colorectal cancer. An altered gut microbiome, linked to weakened immune responses and the production of carcinogenic substances, is a significant contributor to colorectal cancer pathogenesis. Dietary changes that involve low-fiber and phytomolecule intake, coupled with higher consumption of red meat, can raise the risk of colorectal cancer. Salutary filaments, which reach the colon undigested, are metabolized by the gut microbiome, producing short-chain fatty acids. Short-chain fatty acids possess beneficial anti-inflammatory and antiproliferative properties that promote colon health. A well-balanced microbiome, supported by beneficial fibers and phytochemicals, can regulate the activation of proto-oncogenes and oncogenic pathways, thereby reducing cell proliferation. Recent research suggests that an overabundance of specific microbes, such as Fusobacterium nucleatum, may contribute to adverse changes in the colonic mucosa. Positive lifestyle adjustments have been demonstrated to effectively inhibit the growth of harmful opportunistic organisms. Synbiotics, which combine probiotics and prebiotics, can protect the intestinal mucosa by enhancing immune responses and decreasing the production of harmful metabolites, oxidative stress, and cell proliferation. This narrative review provides a concise understanding of evolving evidence regarding how diet influences the gut microbiome, leading to the restoration of the colonic epithelium. It underscores the importance of a healthy, plant-based diet and associated supplements in preventing colorectal cancer by enhancing gut microbiome health.

Could environmental exposure and climate change Be a key factor in the rising incidence of early onset colorectal cancer?

The emergence of early onset colorectal cancer (EOCRC) is believed to result from the complex interplay between external environmental factors and internal molecular processes. This review investigates the potential association between environmental exposure to chemicals and climate change and the increased incidence of EOCRC, focusing on their effects on gut microbiota (GM) dynamics. The manuscript explores the birth cohort effect, suggesting that individuals born after 1950 may be at higher risk of developing EOCRC due to cumulative environmental exposures. Furthermore, we also reviewed the impact of environmental pollution, including particulate matter and endocrine disrupting chemicals (EDCs), as well as global warming, on GM disturbance. Environmental exposures have the potential to disrupt GM composition and diversity, leading to dysbiosis, chronic inflammation, and oxidative stress, which are known risk factors associated with EOCRC. Particulate matter can enter the gastrointestinal tract, modifying GM composition and promoting the proliferation of pathogenic bacteria while diminishing beneficial bacteria. Similarly, EDCs, can induce GM alterations and inflammation, further increasing the risk of EOCRC. Additionally, global warming can influence GM through shifts in gut environmental conditions, affecting the host's immune response and potentially increasing EOCRC risk. To summarize, environmental exposure to chemicals and climate change since 1950 has been implicated as contributing factors to the rising incidence of EOCRC. Disruptions in gut microbiota homeostasis play a crucial role in mediating these associations. Consequently, there is a pressing need for enhanced environmental policies aimed at minimizing exposure to pollutants, safeguarding public health, and mitigating the burden of EOCRC.

Inverse Correlation between pks-Carrying Escherichia coli Abundance in Colorectal Cancer Liver Metastases and the Number of Organs Involved in Recurrence

Colibactin, a genotoxin produced by Escherichia coli strains harboring the polyketide synthetase (pks) gene cluster, causes DNA damage and somatic mutations. pks+E. coli is enriched in primary colorectal cancer (CRC) and is associated with clonal driver mutations, but its role in CRC liver metastasis is unclear. We assessed the association of pks+ E. coli in CRC liver metastasis tissues with systemic and local immune responses and the number of organs involved in recurrence using specimens and clinicopathological data from 239 patients with CRC liver metastasis who underwent metastasectomy. The levels of pks+E. coli in fresh-frozen specimens were quantified as "very low" (<50th percentile), "low" (50th to 75th percentiles), and "high" (>75th percentile) using a digital PCR. Immunohistochemical analysis of tumor-infiltrating immune cells was performed using tissue microarrays. Systemic inflammation was evaluated using serum C-reactive protein (CRP) levels. pks+E. coli was detected in 66.7% (157 of 239) liver metastasis tissues. Higher levels of pks+E. coli were associated with decreased serum CRP levels and reduced densities of CD4+ cells and CD163+ cells in the tumor-immune microenvironment. The "high" pks+ E. coli group had fewer metastatic organs involved than the "very low" pks+ E. coli group (mean number of organs: 1.00 vs. 1.23). These findings suggest that pks+E. coli play a modulating role in CRC metastasis.

Appendix removal affects the subsequent cancer risk in Asian adults: A territory-wide population-based cohort study

Human appendix is critical for the maintenance of intestinal homeostasis. Appendicectomy has been the optimal treatment of acute appendicitis, yet the cancer incidence after appendix removal remains unclear. In this territory-wide retrospective cohort study, adult participants who underwent appendicectomy from 2000 to 2018 were retrieved from a population database (n = 43,983), while matched reference participants were retrieved as controls (n = 85,853). After appendicectomy, the overall cancer risk was significantly increased (subdistribution hazard ratio (SHR) = 1.124) compared to the non-appendicectomy group. Appendicectomy-treated males had higher cancer risk than males without appendicectomy (SHR = 1.197), while such difference was not observed in female participants. Significant increase in cancer risk was also observed in elder participants (age >60) with appendicectomy (SHR = 1.390). Appendicectomy was positively correlated with the risk of digestive tract and respiratory cancers including colon (SHR = 1.440), pancreas (SHR = 1.930), and trachea, bronchus, and lung (SHR = 1.394). In contrast, the risk of liver cancer was markedly decreased after appendicectomy (SHR = 0.713). In conclusion, we reported the association of appendicectomy with subsequent cancer incidence. These findings highlight the potential complication after appendix removal and the necessity of post-operative management to monitor and prevent long-term adverse events.

Microbial genotoxin-elicited host DNA mutations related to mitochondrial dysfunction, a momentous contributor for colorectal carcinogenesis

Gut microbe dysbiosis increases repetitive inflammatory responses, leading to an increase in the incidence of colorectal cancer. Recent studies have revealed that specific microbial species directly instigate mutations in the host nucleus DNA, thereby accelerating the progression of colorectal cancer. Given the well-established role of mitochondrial dysfunction in promoting colorectal cancer, it is reasonable to postulate that gut microbes may induce mitochondrial gene mutations, thereby inducing mitochondrial dysfunction. In this review, we focus on gut microbial genotoxins and their known and potential targets in mitochondrial genes. Consequently, we propose that targeted disruption of genotoxin transport pathways may effectively reduce the rate of mitochondrial gene mutations and yield substantial benefits for the prevention of colorectal carcinogenesis.

Unveiling gut microbiota's role: Bidirectional regulation of drug transport for improved safety

Drug safety is a paramount concern in the field of drug development, with researchers increasingly focusing on the bidirectional regulation of gut microbiota in this context. The gut microbiota plays a crucial role in maintaining drug safety. It can influence drug transport processes in the body through various mechanisms, thereby modulating their efficacy and toxicity. The main mechanisms include: (1) The gut microbiota directly interacts with drugs, altering their chemical structure to reduce toxicity and enhance efficacy, thereby impacting drug transport mechanisms, drugs can also change the structure and abundance of gut bacteria; (2) bidirectional regulation of intestinal barrier permeability by gut microbiota, promoting the absorption of nontoxic drugs and inhibiting the absorption of toxic components; (3) bidirectional regulation of the expression and activity of transport proteins by gut microbiota, selectively promoting the absorption of effective components or inhibiting the absorption of toxic components. This bidirectional regulatory role enables the gut microbiota to play a key role in maintaining drug balance in the body and reducing adverse reactions. Understanding these regulatory mechanisms sheds light on novel approaches to minimize toxic side effects, enhance drug efficacy, and ultimately improve drug safety. This review systematically examines the bidirectional regulation of gut microbiota in drug transportation from the aforementioned aspects, emphasizing their significance in ensuring drug safety. Furthermore, it offers a prospective outlook from the standpoint of enhancing therapeutic efficacy and reducing drug toxicity, underscoring the importance of further exploration in this research domain. It aims to provide more effective strategies for drug development and treatment.

Cancer and the Microbiome of the Human Body

Cancer remains a public health concern worldwide, with its incidence increasing worldwide and expected to continue growing during the next decades. The microbiome has emerged as a central factor in human health and disease, demonstrating an intricate relationship between the microbiome and cancer. Although some microbiomes present within local tissues have been shown to restrict cancer development, mainly by interacting with cancer cells or the host immune system, some microorganisms are harmful to human health and risk factors for cancer development. This review summarizes the recent evidence concerning the microbiome and some of the most common cancer types (i.e., lung, head and neck, breast, gastric, colorectal, prostate, and cervix cancers), providing a general overview of future clinical approaches and perspectives.

Immunomodulation aspects of gut microbiome-related interventional strategies in colorectal cancer

Colorectal cancer (CRC), the third most common cancer worldwide, develops mainly due to the accumulation of genetic and epigenetic changes over many years. Substantial evidence suggests that gut microbiota plays a significant role in the initiation, progression, and control of CRC, depending on the balance between beneficial and pathogenic microorganisms. Nonetheless, gut microbiota composition by regulating the host immune response may either promote or inhibit CRC. Thus, modification of gut microbiota potentially impacts clinical outcomes of immunotherapy. Previous studies have indicated that therapeutic strategies such as probiotics, prebiotics, and postbiotics enhance the intestinal immune system and improve the efficacy of immunotherapeutic agents, potentially serving as a complementary strategy in cancer immunotherapy. This review discusses the role of the gut microbiota in the onset and development of CRC in relation to the immune response. Additionally, we focus on the effect of strategies manipulating gut microbiome on the immune response and efficacy of immunotherapy against CRC. We demonstrate that manipulation of gut microbiome can enhance immune response and outcomes of immunotherapy through downregulating Treg cells and other immunosuppressive cells while improving the function of T cells within the tumor; however, further research, especially clinical trials, are needed to evaluate its efficacy in cancer treatment.

Potential role of the intratumoral microbiota in colorectal cancer immunotherapy

Colorectal cancer (CRC) has been one of the most common malignancies worldwide. Despite the advances in current therapies, the mortality rate of CRC remains high. Among them, immunotherapy has achieved satisfactory results in some CRC patients, however, how to expand the use of immunotherapy in CRC patients remains an urgent challenge. Surprisingly, the intratumoral microbiota has been found in multiple tumor tissues, including CRC. It has been demonstrated that the intratumoral microbiota is associated with the progression and treatment of CRC, and is able to enhance or decrease anti-tumor immune responses via different mechanisms as well as influence the immunotherapy efficacy, providing new potential therapeutic targets for CRC immunotherapy. In this review, we focus on the characteristics of the intratumoral microbiota, its roles in the genesis and development of CRC, its modulation of anti-tumor immune responses and immunotherapy, and propose potential applications of the intratumoral microbiota in CRC immunotherapy. Additionally, we propose possible directions for future research on the intratumoral microbiota related to CRC immunotherapy.

Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum

BACKGROUND

Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled.

AIM

To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps.

METHODS

Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student's t-tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson's correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators.

RESULTS

The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella, Plesiomonas, and Cronobacter, was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones.

CONCLUSION

These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Shaping the future of gastrointestinal cancers through metabolic interactions with host gut microbiota

Gastrointestinal (GI) cancers represent a significant global health challenge, driving relentless efforts to identify innovative diagnostic and therapeutic approaches. Recent strides in microbiome research have unveiled a previously underestimated dimension of cancer progression that revolves around the intricate metabolic interplay between GI cancers and the host's gut microbiota. This review aims to provide a comprehensive overview of these emerging metabolic interactions and their potential to catalyze a paradigm shift in precision diagnosis and therapeutic breakthroughs in GI cancers. The article underscores the groundbreaking impact of microbiome research on oncology by delving into the symbiotic connection between host metabolism and the gut microbiota. It offers valuable insights into tailoring treatment strategies to individual patients, thus moving beyond the traditional one-size-fits-all approach. This review also sheds light on novel diagnostic methodologies that could transform the early detection of GI cancers, potentially leading to more favorable patient outcomes. In conclusion, exploring the metabolic interactions between host gut microbiota and GI cancers showcases a promising frontier in the ongoing battle against these formidable diseases. By comprehending and harnessing the microbiome's influence, the future of precision diagnosis and therapeutic innovation for GI cancers appears more optimistic, opening doors to tailored treatments and enhanced diagnostic precision.

Resistant starch reduces glycolysis by HK2 and suppresses high-fructose corn syrup-induced colon tumorigenesis

BACKGROUND

The intake of high-fructose corn syrup (HFCS) may increase the risk of colorectal cancer (CRC). This study aimed to explore the potential effects and mechanisms of resistant starch (RS) in HFCS-induced colon tumorigenesis.

METHODS

The azoxymethane/dextran sodium sulfate (AOM/DSS) and ApcMin/+ mice models were used to investigate the roles of HFCS and RS in CRC in vivo. An immunohistochemistry (IHC) staining analysis was used to detect the expression of proliferation-related proteins in tissues. 16S rRNA sequencing for microbial community, gas chromatography for short-chain fatty acids (SCFAs), and mass spectrometry analysis for glycolysis products in the intestines were performed. Furthermore, lactic acid assay kit was used to detect the glycolysis levels in vitro.

RESULTS

RS suppressed HFCS-induced colon tumorigenesis through reshaping the microbial community. Mechanistically, the alteration of the microbial community after RS supplement increased the levels of intestinal SCFAs, especially butyrate, leading to the suppression of glycolysis and CRC cell proliferation by downregulating HK2.

CONCLUSIONS

Our study identified RS as a candidate of protective factors in CRC and may provide a potential target for HFCS-related CRC treatment.

Lactococcus lactis HkyuLL 10 suppresses colorectal tumourigenesis and restores gut microbiota through its generated alpha-mannosidase

OBJECTIVE

Probiotic Lactococcus lactis is known to confer health benefits to humans. Here, we aimed to investigate the role of L. lactis in colorectal cancer (CRC).

DESIGN

L. lactis abundance was evaluated in patients with CRC (n=489) and healthy individuals (n=536). L. lactis was isolated from healthy human stools with verification by whole genome sequencing. The effect of L. lactis on CRC tumourigenesis was assessed in transgenic Apc Min/+ mice and carcinogen-induced CRC mice. Faecal microbiota was profiled by metagenomic sequencing. Candidate proteins were characterised by nano liquid chromatography-mass spectrometry. Biological function of L. lactis conditioned medium (HkyuLL 10-CM) and functional protein was studied in human CRC cells, patient-derived organoids and xenograft mice.

RESULTS

Faecal L. lactis was depleted in patients with CRC. A new L. lactis strain was isolated from human stools and nomenclated as HkyuLL 10. HkyuLL 10 supplementation suppressed CRC tumourigenesis in Apc Min/+ mice, and this tumour-suppressing effect was confirmed in mice with carcinogen-induced CRC. Microbiota profiling revealed probiotic enrichment including Lactobacillus johnsonii in HkyuLL 10-treated mice. HkyuLL 10-CM significantly abrogated the growth of human CRC cells and patient-derived organoids. Such protective effect was attributed to HkyuLL 10-secreted proteins, and we identified that α-mannosidase was the functional protein. The antitumourigenic effect of α-mannosidase was demonstrated in human CRC cells and organoids, and its supplementation significantly reduced tumour growth in xenograft mice.

CONCLUSION

HkyuLL 10 suppresses CRC tumourigenesis in mice through restoring gut microbiota and secreting functional protein α-mannosidase. HkyuLL 10 administration may serve as a prophylactic measure against CRC.

Understanding the microbiome as a mediator of bladder cancer progression and therapeutic response

Bladder cancer (BCa) remains a significant source of morbidity and mortality. BCa is one of the most expensive tumors to treat, in part because of a lack of nonsurgical options. The recent advent of immunotherapy, alone or in combination with other compounds, has improved therapeutic options. Resistance to immunotherapy remains common, and many patients do not have durable response. Recent advances indicate immunotherapy efficacy may be tied in part to the endogenous bacteria present in our body, more commonly referred to as the microbiome. Laboratory and clinical data now support the idea that a healthy microbiome is critical to effective response to immunotherapy. At the same time, pathogenic interactions between the microbiome and immune cells can also serve to drive formation of tumors, increasing the complexity of these interactions. Given the rising importance of immunotherapy in BCa, understanding how we might be able to alter the microbiome to improve therapeutic efficacy offers a novel route to improved patient care. The goal of this review is to examine our current understanding of microbial interactions with the immune system and cancer with an emphasis on BCa. We will further attempt to define both current gaps in knowledge and future directions that may yield beneficial results to the field.

Alterations in gut microbiota and inflammatory cytokines after administration of antibiotics in mice

Antibiotics are widely used to treat bacterial infection and reduce the mortality rate, while antibiotic overuse can cause gut microbiota dysbiosis. The impact of antibiotics on gut microbiota is not fully understood. In our study, four commonly used antibiotics (ceftazidime, cefoperazone-sulbactam, imipenem-cilastatin, and moxifloxacin) were given subcutaneously to mice, and their impacts on the gut microbiota composition and serum cytokine levels were evaluated through 16S rRNA analysis and a multiplex immunoassay. Antibiotic treatment markedly reduced gut microbiota diversity and changed gut microbiota composition. Antibiotic treatment significantly increased and decreased the abundance of Firmicutes and Bacteroidota, respectively. The antibiotic treatments increased the abundance of opportunistic pathogens such as Enterococcus and decreased that of Lachnospiraceae and Muribaculaceae. For moxifloxacin, the significantly high abundance of Enterococcus and Klebsiella was observed after 14 and 21 days of treatment. However, a relatively low abundance of opportunistic pathogens was found after 14 days of imipenem-cilastatin treatment. Additionally, the serum levels of various pro-inflammatory cytokines, such as IL-1β, IL-12 (p70), and IL-17, significantly increased after 21 days of antibiotic treatments. Overall, these results provide a guide for rational use of antibiotics in clinical settings: short-term use of moxifloxacin is recommended with regard to gut microbiota health, and the 14-day use of imipenem-cilastatin may have a less severe impact than other antibiotics.IMPORTANCEAntibiotic treatments are directly associated with changes in gut microbiota and are effective against both pathogens and beneficial bacteria. Gut microbiota dysbiosis induced by antibiotic treatment could increase the risk of some diseases. Therefore, an adequate understanding of gut microbiota changes after antibiotic use is crucial. In this study, we investigated the effects of continuous treatment with antibiotics on gut microbiota, serum cytokines, and intestinal inflammatory response. Our results suggest that short-term use of moxifloxacin is recommended, and the 14-day use of imipenem-cilastatin may have a less severe effect on gut microbiota health than cefoperazone-sulbactam. These results provide useful guidance on the rational use of antibiotics with regard to gut microbiota health.

Advancements in 3D In Vitro Models for Colorectal Cancer

The process of drug discovery and pre-clinical testing is currently inefficient, expensive, and time-consuming. Most importantly, the success rate is unsatisfactory, as only a small percentage of tested drugs are made available to oncological patients. This is largely due to the lack of reliable models that accurately predict drug efficacy and safety. Even animal models often fail to replicate human-specific pathologies and human body's complexity. These factors, along with ethical concerns regarding animal use, urge the development of suitable human-relevant, translational in vitro models.

Changes in the gut microbiome of patients with esophageal cancer: A systematic review and meta-analysis based on 16S gene sequencing technology

BACKGROUND

Esophageal cancer (EC) possesses a high degree of malignancy and exhibits poor therapeutic outcomes and prognosis. However, its pathogenesis remains unclear. With the development of macrogene sequencing technology, changes in the intestinal flora have been found to be highly related to the development of EC, although discrepancies and controversies remain in this research area.

MATERIALS AND METHODS

We comprehensively searched the PubMed, EMBASE, and Cochrane's Central Controlled Trials Register and the Scientific Network's database search projects based on systematically reviewed preferred reporting projects and meta-analyses. We used Engauge Digitizer for data extraction and Stata 15.1 for data analysis. In addition, we used the Newcastle-Ottawa Scale for grade grading and forest and funnel plots, sensitivity, and Egger and Beggar tests to evaluate the risk of bias.

RESULTS

This study included 10 studies that assessed stool, tumor, and nontumor esophageal mucosa (gastroscopy and surgical resection) samples from 527 individuals, including 273 patients with EC and 254 healthy control group. We observed remarkable differences in microbial diversity in EC patients compared to healthy controls. The Chao1 index (46.01 vs. 42.67) was significantly increased in EC patients, whereas the Shannon index (14.90 vs. 19.05), ACE (39.24 vs. 58.47), and OTUs(28.93 vs. 70.10) were significantly lower. At the phylum level, the abundance of Bacteroidetes (37.89 vs. 32.77) increased significantly, whereas that of Firmicutes (37.63 vs. 38.72) decreased significantly; the abundance of Clostridium and Verruciformis increased, while that of Actinobacteria and Proteobacteria decreased to varying degrees. The abundance of Bacteroides (8.60 vs. 15.10) and Streptococcaceae (15.08 vs. 27.05) significantly reduced in EC.

CONCLUSIONS

According to our meta-analysis, in patients with EC, the Chao1 index increased, whereas the Shannon and the OTUs decreased. At the phylum level, the abundance of Firmicutes decreased significantly, whereas that of Bacteroidetes and Proteobacteria increased significantly. At the genus/family level, the abundance of Bacteroidaceae, Prevotellaceae and Streptococcaceae decreased significantly, whereas that of Veillonellaceae increased. This meta-analysis identified changes in gut microbiota in patients with EC; however, its conclusions were inconsistent.

Immune Remodeling during Aging and the Clinical Significance of Immunonutrition in Healthy Aging

Aging is associated with changes in the immune system and the gut microbiota. Immunosenescence may lead to a low-grade, sterile chronic inflammation in a multifactorial and dynamic way, which plays a critical role in most age-related diseases. Age-related changes in the gut microbiota also shape the immune and inflammatory responses. Nutrition is a determinant of immune function and of the gut microbiota. Immunonutrion has been regarded as a new strategy for disease prevention and management, including many age-related diseases. However, the understanding of the cause-effect relationship is required to be more certain about the role of immunonutrition in supporting the immune homeostasis and its clinical relevance in elderly individuals. Herein, we review the remarkable quantitative and qualitative changes during aging that contribute to immunosenescence, inflammaging and microbial dysbiosis, and the effects on late-life health conditions. Furthermore, we discuss the clinical significance of immunonutrition in the treatment of age-related diseases by systematically reviewing its modulation of the immune system and the gut microbiota to clarify the effect of immunonutrition-based interventions on the healthy aging.

Microecological regulation in HCC therapy: Gut microbiome enhances ICI treatment

The exploration of the complex mechanisms of cancer immunotherapy is rapidly evolving worldwide, and our focus is on the interaction of hepatocellular carcinoma (HCC) with immune checkpoint inhibitors (ICIs), particularly as it relates to the regulatory role of the gut microbiome. An important basis for the induction of immune responses in HCC is the presence of specific anti-tumor cells that can be activated and reinforced by ICIs, which is why the application of ICIs results in sustained tumor response rates in the majority of HCC patients. However, mechanisms of acquired resistance to immunotherapy in unresectable HCC result in no long-term benefit for some patients. The significant heterogeneity of inter-individual differences in the gut microbiome in response to treatment with ICIs makes it possible to target modulation of specific gut microbes to assist in augmenting checkpoint blockade therapies in HCC. This review focuses on the complex relationship between the gut microbiome, host immunity, and HCC, and emphasizes that manipulating the gut microbiome to improve response rates to cancer ICI therapy is a clinical strategy with unlimited potential.

In situ targeted base editing of bacteria in the mouse gut

Microbiome research is now demonstrating a growing number of bacterial strains and genes that affect our health1. Although CRISPR-derived tools have shown great success in editing disease-driving genes in human cells2, we currently lack the tools to achieve comparable success for bacterial targets in situ. Here we engineer a phage-derived particle to deliver a base editor and modify Escherichia coli colonizing the mouse gut. Editing of a β-lactamase gene in a model E. coli strain resulted in a median editing efficiency of 93% of the target bacterial population with a single dose. Edited bacteria were stably maintained in the mouse gut for at least 42 days following treatment. This was achieved using a non-replicative DNA vector, preventing maintenance and dissemination of the payload. We then leveraged this approach to edit several genes of therapeutic relevance in E. coli and Klebsiella pneumoniae strains in vitro and demonstrate in situ editing of a gene involved in the production of curli in a pathogenic E. coli strain. Our work demonstrates the feasibility of modifying bacteria directly in the gut, offering a new avenue to investigate the function of bacterial genes and opening the door to the design of new microbiome-targeted therapies.

The Role of Adipocytes Recruited as Part of Tumor Microenvironment in Promoting Colorectal Cancer Metastases

Adipose tissue dysfunction, which is associated with an increased risk of colorectal cancer (CRC), is a significant factor in the pathophysiology of obesity. Obesity-related inflammation and extracellular matrix (ECM) remodeling promote colorectal cancer metastasis (CRCM) by shaping the tumor microenvironment (TME). When CRC occurs, the metabolic symbiosis of tumor cells recruits adjacent adipocytes into the TME to supply energy. Meanwhile, abundant immune cells, from adipose tissue and blood, are recruited into the TME, which is stimulated by pro-inflammatory factors and triggers a chronic local pro-inflammatory TME. Dysregulated ECM proteins and cell surface adhesion molecules enhance ECM remodeling and further increase contractibility between tumor and stromal cells, which promotes epithelial-mesenchymal transition (EMT). EMT increases tumor migration and invasion into surrounding tissues or vessels and accelerates CRCM. Colorectal symbiotic microbiota also plays an important role in the promotion of CRCM. In this review, we provide adipose tissue and its contributions to CRC, with a special emphasis on the role of adipocytes, macrophages, neutrophils, T cells, ECM, and symbiotic gut microbiota in the progression of CRC and their contributions to the CRC microenvironment. We highlight the interactions between adipocytes and tumor cells, and potential therapeutic approaches to target these interactions.

The intestinal flora and nutritional status and immune function characteristics of obese colon cancer patients

BACKGROUND

The research aims to explore the characteristics of intestinal flora, nutritional status and immune function in patients with different types of obese colon cancer.

METHODS

A retrospective analysis is conducted on 64 cases of obese colon cancer diagnosed from June 2018 to January 2020. According to the histological staging of the cancer, they are classified into adenocarcinoma, adenosquamous carcinoma and undifferentiated carcinoma, with corresponding cases of 24, 22 and 18, respectively. The intestinal flora (Bifidobacterium, Lactobacillus, Enterococcus faecalis, Escherichia coli, and yeast), nutritional status (Hb, Alb, PA, TFN, and PNI), immune function (IgG, IgM, IgA, CD4+, CD8+, and CD4+/CD8+) are analyzed in the different groups of patients. Survival curves are evaluated by Kaplan-Meier method and log-rank test for tumour death, local recurrence, and distant metastasis.

RESULTS

There were no statistically significant differences in intestinal flora (Bifidobacterium, Lactobacillus, Enterococcus faecalis, Escherichia coli, and yeast), nutritional status (Hb, Alb, PA, TFN, and PNI) and immune function (IgG, IgM, IgA, CD4+, CD8+, and CD4+/CD8+) between different groups. There was a significant correlation between intestinal flora, nutritional status and immune function for all three. The survival curves of tumour death, local recurrence and distant metastasis in different groups of obese colon cancer patients were statistically significant. The tumor mortality rate, local recurrence, and distant metastasis rate in adenocarcinoma were 78.65%, 54.25% and 48.26% respectively.

CONCLUSION

There are differences in intestinal flora, nutritional status and immune function among different types of obese colon cancer patients, but adenocarcinoma has the least benefit in intestinal flora, poor nutritional status, and weakest immune function.

Risk of colorectal cancer and adenoma after an appendectomy: results from three large prospective cohort studies and meta-analysis

PURPOSE

The relationship between appendectomy and subsequent colorectal cancer risk remains unclear, and no study has examined its association with colorectal adenoma.

METHODS

We used data from three prospective cohorts: Health Professionals Follow-up Study, Nurses' Health Study (NHS), and NHSII. Appendectomy history was self-reported at baseline. Colorectal cancer risk was analyzed with Cox proportional hazard models among 224,109 participants followed up to 32 years. Colorectal adenoma risk was evaluated among 157,490 participants with at least one lower gastrointestinal endoscopy during follow-up with logistic regression models accounting for repeated observations. We also performed a meta-analysis of cohort studies that examined association between appendectomy and colorectal cancer risk.

RESULTS

We documented 3,384 colorectal cancers, 13,006 conventional adenomas, and 11,519 serrated polyps during the follow-up period. Compared to participants without appendectomy, those who reported appendectomy history were not at higher risk of colorectal (HR [95% CI], 0.92 [0.84-1.00]), colon (0.92 [0.83-1.01]), or rectal (0.85 [0.70-1.03]) cancer. Similarly, appendectomy history was not associated with higher risk of conventional adenoma (OR [95% CI], 1.00 [0.97-1.02]), serrated polyp (0.97 [0.94-1.00]), or high-risk adenoma (0.96 [0.92-1.01]). The meta-analysis showed appendectomy was associated with a higher risk of colorectal cancer within a short time after the procedure (1.68 [1.01-2.81]), while the long-term risk was slightly inverse (0.94 [0.90-0.97]).

CONCLUSION

We found no evidence of an association between appendectomy history and long-term risk of colorectal cancer or its precursors. The observed higher risk of colorectal cancer right after appendectomy in the first few years is likely due to reverse causation.

Gut microbiota affects the activation of STING pathway and thus participates in the progression of colorectal cancer

BACKGROUND

More and more studies showed that gut microbiota was closely related to the development of colorectal cancer (CRC). However, the specific pathway of gut microbiota regulating CRC development is still unknown.

METHODS

We collected fecal samples from 14 CRC patients and 20 normal volunteers for 16 S sequencing analysis. At the same time, 14 CRC patients' tumors and their adjacent tissues were collected for the detection of STING pathway related protein level. Mice were injected with azoxymethane (AOM) to establish an animal model of CRC, and antibiotics were given at the same time to evaluate the influence of gut microbiota on STING pathway and whether it was involved in regulating the tumor development of CRC mice.

RESULTS

The sequencing results showed that compared with the normal group, the gut microbiota gut microbiota of CRC patients changed significantly at different species classification levels. At the level of genus, Akkermansia, Ligilactobacillus and Subdoligranulum increased the most in CRC patients, while Bacteroides and Dialister decreased sharply. The expression of STING-related protein was significantly down-regulated in CRC tumor tissues. Antibiotic treatment of CRC mice can promote the development of tumor and inhibit the activation of STING pathway.

CONCLUSION

Gut microbiota participates in CRC progress by mediating STING pathway activation.

Antioxidant, Antitumoral, Antimicrobial, and Prebiotic Activity of Magnetite Nanoparticles Loaded with Bee Pollen/Bee Bread Extracts and 5-Fluorouracil

The gut microbiota dysbiosis that often occurs in cancer therapy requires more efficient treatment options to be developed. In this concern, the present research approach is to develop drug delivery systems based on magnetite nanoparticles (MNPs) as nanocarriers for bioactive compounds. First, MNPs were synthesized through the spraying-assisted coprecipitation method, followed by loading bee pollen or bee bread extracts and an antitumoral drug (5-fluorouracil/5-FU). The loaded-MNPs were morphologically and structurally characterized through transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Dynamic Light Scattering (DLS), and thermogravimetric analysis. UV-Vis spectroscopy was applied to establish the release profiles and antioxidant activity. Furthermore, the antibacterial and antitumoral activity of loaded-MNPs was assessed. The results demonstrate that MNPs with antioxidant, antibacterial, antiproliferative, and prebiotic properties are obtained. Moreover, the data highlight the improvement of 5-FU antibacterial activity by loading on the MNPs' surface and the synergistic effects between the anticancer drug and phenolic compounds (PCs). In addition, the prolonged release behavior of PCs for many hours (70-75 h) after the release of 5-FU from the developed nanocarriers is an advantage, at least from the point of view of the antioxidant activity of PCs. Considering the enhancement of L. rhamnosus MF9 growth and antitumoral activity, this study developed promising drug delivery alternatives for colorectal cancer therapy.

The Microbiota in Cancer: A Secondary Player or a Protagonist?

The intestinal microbiota and the human body are in a permanent interaction. There is a symbiotic relationship in which the microbiota plays a vitally important role in the performance of numerous functions, including digestion, metabolism, the development of lymphoid tissue, defensive functions, and other processes. It is a true metabolic organ essential for life and has potential involvement in various pathological states, including cancer and pathologies other than those of a digestive nature. A growing topic of great interest for its implications is the relationship between the microbiota and cancer. Dysbiosis plays a role in oncogenesis, tumor progression, and even the response to cancer treatment. The effect of the microbiota on tumor development goes beyond a local effect having a systemic effect. Another aspect of great interest regarding the intestinal microbiota is its relationship with drugs, modifying their activity. There is increasing evidence that the microbiota influences the therapeutic activity and side effects of antineoplastic drugs and also modulates the response of several tumors to antineoplastic therapy through immunological circuits. These data suggest the manipulation of the microbiota as a possible adjuvant to improve oncological treatment. Is it possible to manipulate the microbiota for therapeutic purposes?

Research progress on the correlation between intestinal flora and colorectal cancer

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies in the world. With the rapid pace of life and changes in diet structure, the incidence and mortality of CRC increase year by year posing a serious threat to human health. As the most complex and largest microecosystem in the human body, intestinal microecology is closely related to CRC. It is an important factor that affects and participates in the occurrence and development of CRC. Advances in next-generation sequencing technology and metagenomics have provided new insights into the ecology of gut microbes. It also helps to link intestinal flora with CRC, and the relationship between intestinal flora and CRC can be continuously understood from different levels. This paper summarizes the relationship between intestinal flora and CRC and its potential role in the diagnosis of CRC providing evidence for early screening and treatment of CRC.

Gut microbiota-lncRNA/circRNA crosstalk: implications for different diseases

The gut microbiota features an abundance of diverse microorganisms and represents an important component of human physiology and metabolic homeostasis, indicating their roles in a wide array of physiological and pathological processes in the host. Maintaining balance in the gut microbiota is critical for normal functionality as microbial dysbiosis can lead to the occurrence and development of diseases through various mechanisms. Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are non-coding RNAs that perform important regulatory functions for many processes. Furthermore, the gut microbiota and lncRNAs/circRNAs are known to interact in a range of both physiological and pathological activities. In this article, we review existing research relevant to the interaction between the gut microbiota and lncRNAs/circRNAs and investigate the role of their crosstalk in the pathogenesis of different diseases. Studies have shown that, the gut microbiota can target lncRNAs ENO1-IT1, BFAL1, and LINC00152 to regulate colorectal cancer development via various signaling pathways. In addition, the gut microbiota can influence mental diseases and lung tumor metastasis by modulating circRNAs such as circNF1-419, circ_0001239, circHIPK2 and mmu_circ_0000730. These findings provide a theoretical basis for disease prevention and treatment and suggest that gut microbiota-lncRNA/circRNA crosstalk has high clinical value.

Ginsenoside Rh4 inhibits colorectal cancer via the modulation of gut microbiota-mediated bile acid metabolism

INTRODUCTION

Dysbiosis of the gut microbiota is emerging as a pivotal factor in the pathogenesis of colorectal cancer (CRC). Ginsenoside Rh4 (Rh4) is an active compound isolated from ginseng with beneficial effects in modulating intestinal inflammation and gut microbiota dysbiosis, but how Rh4 regulates the gut microbiota to alleviate CRC remains underexplored.

OBJECTIVES

We investigated the impact of Rh4 on CRC and the mechanism of its action in inhibiting CRC via modulation of gut microbiota.

METHODS

We used the AOM/DSS model and employed transcriptomics, genomics and metabolomics techniques to explore the inhibitory impact of Rh4 on CRC. Furthermore, we employed experiments involving antibiotic treatment and fecal microbiota transplantation (FMT) to investigate the role of the gut microbiota. Finally, we elucidated the pivotal role of key functional bacteria and metabolites regulated by Rh4 in CRC.

RESULTS

Our research findings indicated that Rh4 repaired intestinal barrier damage caused by CRC, alleviated intestinal inflammation, and inhibited the development of CRC. Additionally, Rh4 inhibited CRC in a gut microbiota-dependent manner. Rh4 increased the diversity of gut microbiota, enriched the probiotic Akkermansia muciniphila (A. muciniphila), and alleviated gut microbiota dysbiosis caused by CRC. Subsequently, Rh4 regulated A. muciniphila-mediated bile acid metabolism. A. muciniphila promoted the production of UDCA by enhancing the activity of 7α-hydroxysteroid dehydrogenase (7α-HSDH). UDCA further activated FXR, modulated the TLR4-NF-κB signaling pathway, thus inhibiting the development of CRC.

CONCLUSION

Our results confirm that Rh4 inhibits CRC in a gut microbiota-dependent manner by modulating gut microbiota-mediated bile acid metabolism and promoting the production of UDCA, which further activates the FXR receptor and regulates the TLR4-NF-κB signaling pathway. Our results confirm that Rh4 has the potential to be used as a modulator of gut microbiota for preventing and treatment of CRC.

Research Advances of Lipid Nanoparticles in the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a common type of gastrointestinal tract (GIT) cancer and poses an enormous threat to human health. Current strategies for metastatic colorectal cancer (mCRC) therapy primarily focus on chemotherapy, targeted therapy, immunotherapy, and radiotherapy; however, their adverse reactions and drug resistance limit their clinical application. Advances in nanotechnology have rendered lipid nanoparticles (LNPs) a promising nanomaterial-based drug delivery system for CRC therapy. LNPs can adapt to the biological characteristics of CRC by modifying their formulation, enabling the selective delivery of drugs to cancer tissues. They overcome the limitations of traditional therapies, such as poor water solubility, nonspecific biodistribution, and limited bioavailability. Herein, we review the composition and targeting strategies of LNPs for CRC therapy. Subsequently, the applications of these nanoparticles in CRC treatment including drug delivery, thermal therapy, and nucleic acid-based gene therapy are summarized with examples provided. The last section provides a glimpse into the advantages, current limitations, and prospects of LNPs in the treatment of CRC.

Emerging importance of stool preservation methods in OMICS studies with special focus on cancer biology

The intricate consortium of microorganisms in the human gut plays a crucial role in different physiological functions. The complex known-unknown elements of the gut microbiome are perplexing and the absence of standardized procedures for collecting and preserving samples has hindered continuous research in comprehending it. The technological bias produced because of lack of standard protocols has affected the reproducibility of results. The complex nature of diseases like colorectal cancer, gastric cancer, hepatocellular carcinoma and breast cancer require a thorough understanding of its etiology for an efficient and timely diagnosis. The designated protocols for collection and preservation of stool specimens have great variance, hence generate inconsistencies in OMICS studies. Due to the complications associated to the nature of sample, it is important to preserve the sample to be studied later in a laboratory or to be used in the future research purpose. Stool preservation is gaining importance due to the increased use of treatment options like fecal microbiota transplantation to cure conditions like recurrent Clostridium difficile infections and for OMICS studies including metagenomics, metabolomics and culturomics. This review provides an insight into the importance of omics studies for the identification and development of novel biomarkers for quick and noninvasive diagnosis of various diseases.

Harnessing human microbiomes for disease prediction

The human microbiome has been increasingly recognized as having potential use for disease prediction. Predicting the risk, progression, and severity of diseases holds promise to transform clinical practice, empower patient decisions, and reduce the burden of various common diseases, as has been demonstrated for cardiovascular disease or breast cancer. Combining multiple modifiable and non-modifiable risk factors, including high-dimensional genomic data, has been traditionally favored, but few studies have incorporated the human microbiome into models for predicting the prospective risk of disease. Here, we review research into the use of the human microbiome for disease prediction with a particular focus on prospective studies as well as the modulation and engineering of the microbiome as a therapeutic strategy.

Mechanisms and clinical landscape of N6-methyladenosine (m6A) RNA modification in gastrointestinal tract cancers

Epigenetics encompasses reversible and heritable chemical modifications of non-nuclear DNA sequences, including DNA and RNA methylation, histone modifications, non-coding RNA modifications, and chromatin rearrangements. In addition to well-studied DNA and histone methylation, RNA methylation has emerged as a hot topic in biological sciences over the past decade. N6-methyladenosine (m6A) is the most common and abundant modification in eukaryotic mRNA, affecting all RNA stages, including transcription, translation, and degradation. Advances in high-throughput sequencing technologies made it feasible to identify the chemical basis and biological functions of m6A RNA. Dysregulation of m6A levels and associated modifying proteins can both inhibit and promote cancer, highlighting the importance of the tumor microenvironment in diverse biological processes. Gastrointestinal tract cancers, including gastric, colorectal, and pancreatic cancers, are among the most common and deadly malignancies in humans. Growing evidence suggests a close association between m6A levels and the progression of gastrointestinal tumors. Global m6A modification levels are substantially modified in gastrointestinal tumor tissues and cell lines compared to healthy tissues and cells, possibly influencing various biological behaviors such as tumor cell proliferation, invasion, metastasis, and drug resistance. Exploring the diagnostic and therapeutic potential of m6A-related proteins is critical from a clinical standpoint. Developing more specific and effective m6A modulators offers new options for treating these tumors and deeper insights into gastrointestinal tract cancers.

Molecular subtypes of colorectal cancer in the era of precision oncotherapy: Current inspirations and future challenges

BACKGROUND

Colorectal cancer (CRC) is among the most hackneyed malignancies. Even patients with identical clinical symptoms and the same TNM stage still exhibit radically different clinical outcomes after receiving equivalent treatment regimens, indicating extensive heterogeneity of CRC. Myriad molecular subtypes of CRC have been exploited for decades, including the most compelling consensus molecular subtype (CMS) classification that has been broadly applied for patient stratification and biomarker-drug combination formulation. Encountering barriers to clinical translation, however, CMS classification fails to fully reflect inter- or intra-tumor heterogeneity of CRC. As a consequence, addressing heterogeneity and precisely managing CRC patients with unique characteristics remain arduous tasks for clinicians.

REVIEW

In this review, we systematically summarize molecular subtypes of CRC and further elaborate on their clinical applications, limitations, and future orientations.

CONCLUSION

In recent years, exploration of subtypes through cell lines, animal models, patient-derived xenografts (PDXs), organoids, and clinical trials contributes to refining biological insights and unraveling subtype-specific therapies in CRC. Therapeutic interventions including nanotechnology, clustered regulatory interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9), gut microbiome, and liquid biopsy are powerful tools with the possibility to shift the immunologic landscape and outlook for CRC precise medicine.

Non-invasive early detection on esophageal squamous cell carcinoma and precancerous lesions by microbial biomarkers combining epidemiological factors in China

BACKGROUND

Microbiota may be associated with esophageal squamous cell carcinoma (ESCC) development. However, it is not known the predictive value of microbial biomarkers combining epidemiological factors for the early detection of ESCC and precancerous lesions.

METHODS

A total of 449 specimens (esophageal swabs and saliva) were collected from 349 participants with different esophageal statuses in China to explore and validate ESCC-associated microbial biomarkers from genes level to species level by 16S rRNA sequencing, metagenomic sequencing and real-time quantitative polymerase chain reaction.

RESULTS

A bacterial biomarker panel including Actinomyces graevenitzii (A.g_1, A.g_2, A.g_3, A.g_4), Fusobacteria nucleatum (F.n_1, F.n_2, F.n_3), Haemophilus haemolyticus (H.h_1), Porphyromonas gingivalis (P.g_1, P.g_2, P.g_3) and Streptococcus australis (S.a_1) was explored by metagenomic sequencing to early detect the participants in Need group (low-grade intraepithelial neoplasia, high-grade intraepithelial neoplasia and ESCC) vs participants without these lesions as the Noneed group. Significant quantitative differences existed for each microbial target in which the detection efficiency rate was higher in saliva than esophageal swab. In saliva, the area under the curve (AUC) based on the microbial biomarkers (A.g_4 ∩ P.g_3 ∩ H.h_1 ∩ S.a_1 ∩ F.n_2) was 0.722 (95% CI 0.621-0.823) in the exploration cohort. Combining epidemiological factors (age, smoking, drinking, intake of high-temperature food and toothache), the AUC improved to 0.869 (95% CI 0.802-0.937) in the exploration cohort, which was validated with AUC of 0.757 (95% CI 0.663-0.852) in the validation cohort.

CONCLUSIONS

It is feasible to combine microbial biomarkers in saliva and epidemiological factors to early detect ESCC and precancerous lesions in China.

Third-generation PacBio sequencing to explore gut bacteria and gender in colorectal cancer

BACKGROUND

Gut bacteria have an important influence on colorectal cancer (CRC). The differences of gut bacteria between genders have been the hot spots.

OBJECTIVE

To analyze the relationship between gut bacteria and gender differences in patients with CRC.

METHODS

A total of 212 patients with CRC and 212 healthy volunteers were recruited. The subjects' fecal samples were obtained, and the fecal microorganisms were analyzed by the third-generation sequencing PacBio. The composition of gut bacteria was analyzed. Linear discriminant analysis Effect Size (LEfSe) was used to analyze the differences in gut bacteria. Pearson coefficient was used to calculate the correlation between differential bacteria. CRC risk prediction models were used to rank the importance of effective differential bacteria.

RESULTS

Escherichia flexneri and Phocaeicola vulgatus were the most frequent bacteria in both male and female CRC patients. Bacteroides, Verrucomicrobia and Akkermansiaceae were highly enriched in male CRC group, while Bacteroidetes, Phocaeicola and Tissierellales were highly enriched in female CRC group. Peptostreptococcus anaerobius and Phocaeicola vulgatus were important CRC related bacteria in males and females, respectively. Peptostreptococcus anaerobius was the most important characteristic bacterium of males (AUC = 0.951), and the sensitivity and specificity of the discovery set were 78.74 % and 93.98 %, respectively. Blautia stercoris was the most important characteristic bacterium of females (AUC = 0.966), and the sensitivity and specificity of the discovery set were 90.63 % and 90.63 %, respectively.

CONCLUSION

Gut bacteria varied in different genders. Therefore, gender should be considered when gut bacteria are applied in the diagnose and prevention of CRC.